Apolipoprotein A-I been isolated, and characterized from patients homozygous for Tangier Disease. ApoA-Tangier were shown to have increased isoform heterogeneity, larger apparent molecular weight, and different amino acid composition when compared to normal apoA-I. These studies in conjunction with metabolic studies indicate that the molecular defect in Tangier disease is a structural defect in apoA-I-Tangier. The polymorphic forms of apoB (B-48, B-100) have been characterized in patients with phenotypes I to V. B-48 was present in VLDL patients with phenotypes I and V when triglucerides were greater then 1000, and in all type III patients. B-48 appears to be a metabolic marker for intestinal lipoproteins. Human parathyroid hormone (1-84) has been synthesized by solid phase techniques. The syntetic hormone is identical to the native hormone in physico-chemical properaties and biological activity.